laser induced separation of isotopes
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Laser Induced Separation of IsotopesTRANSCRIPT
Laser induced separation Laser induced separation
of isotopesof isotopes
atomic structureatomic structure
•Atoms are made up of three main particles.
These are the neutron, electron, and proton.
These main parts are each made up of smaller
particles. The last picture shows the placement
of each of the main particles .
•What are?•Isotopes, Isobars , Isotones and
isomers
IsotopesIsotopes
•These are the elements having same atomic
number but different mass number. They
have the same atomic number because the
number of protons inside their nuclei
remains the same. The difference in their
mass number is due to the difference in
their number of neutrons
Examples Examples •Hydrogen Isotopes:
•Hydrogen) 1H1 (
Tritium 1H3- Deuterium) 1H2(
ISOMERSISOMERS
•molecular are compounds with the same
. structural formulasbut different formula
Isomers do not necessarily share similar
properties, unless they also have the
. There are many functional groupssame
different classes of isomers, like
stereoisomers, enantiomers, geometrical
isomers, etc
IsobarsIsobars
•Isotopes are chemically same and physically
different. But the converse is true in isobars.
That is isobars are elements, which are
chemically different but physically same. So,
isobars are atoms of different elements having
the same atomic mass but different atomic
number. Since their number of electrons is
different, their chemical properties are
different.
Examples of isobarsExamples of isobars
•Since isobars are different elements they
appear in different places in the periodic
table.
IsotonesIsotones
•Isotones are elements having the same number
of neutrons.
•Examples of isotones are :-
•Chlorine - 37 and Potassium - 39.
•Both have 20 neutrons in their nuclei.
Isotopes Separation
•Is purification specific isotope by removing
unwanted impurities .
•Most separation techniques rely on the
difference of masses of the isotope species
involved .
Deuterium has twice the mass as hydrogen and
is generally easier to purify than uranium 235
and uranium 238 .
Importance of isotopes separationImportance of isotopes separation
•scientific researches-1
•Radiochemical
•Using radioactive materials for analytical measurement purposes and radiometric .
•Radioisotopic
•Use of radionuclides to study biological , chemical , geological and physical processes in the environment .
•Medicine-2
•Nuclear Energy-3
•Nuclear Weapons-4
•
Practical methods of Practical methods of isotopesisotopes
separationseparation
•Diffusion
•Often done with gases, but also with liquids, the method relies on the fact that in thermal diffusion
equilibrium, two isotopes with the same energy will have different average velocities. The lighter atoms (or the molecules containing them) will travel more quickly and be more likely to diffuse through a membrane. The difference in speeds is proportional to the square root of the mass ratio, so the amount of separation is small and many cascaded stages are needed to obtain high purity. This method is expensive due to the work needed to push gas through a membrane and the many stages necessary.
Centrifugal effectCentrifugal effect
•. In modern times it is the main method used
throughout the world to enrich uranium and as
a result remains a fairly secretive process,
hindering a more widespread uptake of the
technology.
ElectromagneticElectromagnetic
•It uses the fact that charged particles are and the amount of magnetic fielddeflected in a
deflection depends upon the particle's mass. It is very expensive for the quantity produced, as it has an extremely low throughput, but it can allow very high purities to be achieved. This method is often used for processing small amounts of pure isotopes for research or
but is ), isotopic tracersspecific use (such as impractical for industrial use.
Chemical methodsChemical methods
•Techniques using this are most effective for
light atoms such as hydrogen. Lighter isotopes
more quickly than evaporatetend to react or
heavy isotopes, allowing them to be separated.
GravityGravity
•Isotopes of Carbon, Oxygen, and Nitrogen can
be purified by chilling these gases or
compounds nearly to their liquification
temperature in very tall columns (200 to 700
feet tall - 70 to 200 meters). The heavier
isotopes sink and the lighter isotopes rise,
where they are easily collected.
Laser isotope separation LISLaser isotope separation LIS
•Laser isotope separation is a general and
•powerful method in which a selected
•isotope is enriched or depleted, using
•remarkable properties of laser radiation.
How LIS WorksHow LIS Works
•Laser isotope separation (LIS) is based on the
fact that different isotopes of the same
element, while chemically identical, have
different electronic energies and therefore
absorb different colors of laser light. The
isotopes of most elements can be separated by
a laser-based process if they can be efficiently
vaporized as atoms.
LIS techniqueLIS technique
•In LIS enrichment, uranium metal is first vaporized in
a separator unit contained in a vacuum chamber. The
vapor stream is then illuminated with laser light tuned
precisely to a color at which 235U absorbs energy.
The generation of laser light starts with diode-
pumped, solid-state lasers providing short, high-
intensity pulses at high repetition rates. This green
light from the solid-state lasers travels via fiber-optic
cable to energize high-power dye lasers. The dye
laser absorbs green light and reemits it at a color that
can be tuned to the isotope of interest. In uranium
enrichment, the light converts to three wavelengths of
red-orange light, which is absorbed only by 235U
•Each color selectively adds enough energy to ionize or remove an electron from 235U atoms, leaving other isotopes unaffected. "The uranium atoms are subjected to a razor-sharp beam," notes Livermore physicist Steve Hargrove. "Given the several kilowatts of high average power of the dye laser beam, it's a significant achievement that the wavelengths are stable to better than 1 part in 10 million and that the beam's ability to travel long distances is nearly perfectly preserved
•Because the ionized 235U atoms are now
"tagged" with a positive charge, they are easily
collected on negatively charged surfaces inside
the separator unit. The product material is
condensed as liquid on these surfaces and then
flows to a caster where it solidifies as metal
nuggets. The unwanted isotopes, which are
unaffected by the laser beam, pass through the
product collector, condense on the tailings
collector, and are removed .